How do I get smooth edges with OpenGL on Android?

Question

Here is a screenshot that maybe makes clear what my problem is.

I'm only drawing 2D circles with OpenGL.

I already read the following:

• https://stackoverflow.com/questions/3512456/how-to-draw-smooth-line-with-antialias
• How to draw a smooth circle in Android using OpenGL?
• https://stackoverflow.com/questions/4934367/how-to-get-rid-of-jagged-edges-in-android-opengl-es

and added the blending function. But nothing worked or even made a difference.

This is my renderer:

public class GLRendererTamago implements Renderer{


private GLTamago tama;


public GLRendererTamago(){

    tama = new GLTamago();
}

@Override
public void onSurfaceCreated(GL10 gl, EGLConfig config) {
    gl.glDisable(GL10.GL_DITHER);
    gl.glDisable(GL10.GL_DEPTH_TEST);
    gl.glEnable(GL10.GL_BLEND); 
    gl.glBlendFunc(GL10.GL_SRC_ALPHA, GL10.GL_ONE_MINUS_SRC_ALPHA);
    gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_FASTEST);
    gl.glClearColor(.8f, 0f, .2f, 1f);
    gl.glClearDepthf(1f);
}

@Override
public void onDrawFrame(GL10 gl) {
    gl.glDisable(GL10.GL_DITHER);
    gl.glDisable(GL10.GL_DEPTH_TEST);
    gl.glMatrixMode(GL10.GL_MODELVIEW);
    gl.glLoadIdentity();
    GLU.gluLookAt(gl, 0, 0, -5, 0, 0, 0, 0, 2, 0);

    tama.draw(gl);
}

@Override
public void onSurfaceChanged(GL10 gl, int width, int height) {
    // TODO Automatisch generierter Methodenstub
    gl.glViewport(0, 0, width, height);
    float ratio = (float)width / height;
    gl.glMatrixMode(GL10.GL_PROJECTION);
    gl.glLoadIdentity();
    gl.glFrustumf(-ratio, ratio, -1, 1, 1, 20);

}

and this my object:

public class GLTamago{

private int points = 1000;
private float vertices[]={0.0f,0.0f,0.0f};
private FloatBuffer vertBuff;



public GLTamago(){

    vertices = new float[points * 2];
    for(int i=0; i< points; i+=3)
    {
      double rad = 2*(Math.PI *i) / points; 

      vertices[i]=(float)Math.cos(rad);     
      vertices[i+1]=(float)Math.sin(rad);   
      vertices[i+2]=0;              
    }  

    ByteBuffer bBuff=ByteBuffer.allocateDirect(vertices.length*4);    
    bBuff.order(ByteOrder.nativeOrder());
    vertBuff=bBuff.asFloatBuffer();
    vertBuff.put(vertices);
    vertBuff.position(0);
}

public void draw(GL10 gl){
    body(gl);
    lefteye(gl);
    righteye(gl);
    mouth(gl);
 }  

private void body (GL10 gl){
    gl.glPushMatrix();
    gl.glTranslatef(0, 0, 0);
    gl.glScalef(2.0f, 3.0f, 1.0f); //Skalierung einstellen
    gl.glColor4f(1.0f,1.0f,1.0f, 1.0f); 
    gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertBuff);
    gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
    gl.glDrawArrays(GL10.GL_TRIANGLE_FAN, 0, points/2);
    gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
    gl.glPopMatrix();
}

private void lefteye (GL10 gl){
    gl.glPushMatrix();
    gl.glTranslatef(1, 1, 0);
    gl.glScalef(0.5f, 0.5f, 1.0f); //Skalierung einstellen
    gl.glColor4f(0.0f,0.0f,0.0f, 1.0f); 
    gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertBuff);
    gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
    gl.glDrawArrays(GL10.GL_TRIANGLE_FAN, 0, points/2);
    gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
    gl.glPopMatrix();

    gl.glPushMatrix();
    gl.glTranslatef(1, 1, 0);
    gl.glScalef(0.1f, 0.1f, 1.0f); //Skalierung einstellen
    gl.glColor4f(1.0f,1.0f,1.0f, 1.0f); 
    gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertBuff);
    gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
    gl.glDrawArrays(GL10.GL_TRIANGLE_FAN, 0, points/2);
    gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
    gl.glPopMatrix();
}

private void righteye (GL10 gl){
    gl.glPushMatrix();
    gl.glTranslatef(-1, 1, 0);
    gl.glScalef(0.5f, 0.5f, 1.0f); //Skalierung einstellen
    gl.glColor4f(0.0f,0.0f,0.0f, 1.0f); 
    gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertBuff);
    gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
    gl.glDrawArrays(GL10.GL_TRIANGLE_FAN, 0, points/2);
    gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
    gl.glPopMatrix();

    gl.glPushMatrix();
    gl.glTranslatef(-1, 1, 0);
    gl.glScalef(0.1f, 0.1f, 1.0f); //Skalierung einstellen
    gl.glColor4f(1.0f,1.0f,1.0f, 1.0f); 
    gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertBuff);
    gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
    gl.glDrawArrays(GL10.GL_TRIANGLE_FAN, 0, points/2);
    gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
    gl.glPopMatrix();

}   


private void mouth (GL10 gl){
    gl.glPushMatrix();
    gl.glTranslatef(0.0f, -1.0f, 0.0f);
    gl.glScalef(1.8f, 0.5f, 1.0f); //Skalierung einstellen
    gl.glColor4f(0.0f,0.0f,0.0f, 1.0f); 
    gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertBuff);
    gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
    gl.glDrawArrays(GL10.GL_TRIANGLE_FAN, 0, points/2);
    gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
    gl.glPopMatrix();
}
}

At the edges you can see pixels... and I have no idea how I can fix this.

I often heard to try anti-aliasing and/or shaders... but I don't have any idea how that works etc.

Answer 1

I solved the problem with the EGLConfigChooser.

I have no idea what that is doing... but it works very fine.

I just copyed the code from here:

http://code.google.com/p/gdc2011-android-opengl/source/browse/trunk/src/com/example/gdc11/MultisampleConfigChooser.java

in a new class and made as it told me:

To use this, call myGLSurfaceView.setEGLConfigChooser(new MultisampleConfigChooser()); before calling setRenderer().